Integrated dry material reducing and classifying means



July 19, 1960 H. cs. LYKKEN EFAL 2,945,633

INTEGRATED DRY MATERIAL REDUCING AND CLASSIFYING MEANS A Sheets-Sheet 1 IN V EN TORS Arroxuer:

Filed Dec. 19, 1955 //EWRY 6. Law/(av BY Mumnbfilykxzw July 19, 1960 H. cs. LYKKEN ET AL I INTEGRATED DRY MATERIAL REDUCING AND CLASSIFYING MEANS Filed Dec. 19, 1955 4 Sheets-Sheet 2 INVENTORS l/ENRY 6. zyxxav BY Will/4M M l YAKE/V M9WW1MWW A ffmwvEY-f July 19, 1960 H LYKKEN EI'AL 2,945,633

INTEGRATED DRY MATERIAL REDUCING AND CLASSIFYING MEANS Filed Dec. 19, 1955 4 Sheets-Sheet '3 INVENTORS HENRY 6. zmwzu BY N/LL/AM 1V. lYK/(EAI 4rroxmsys July 19, 1960 H. G. LYKKEN ETAL 2,945,633

INTEGRATED DRY MATERIAL REDUCING AND CLASSIFYING MEANS Filed Dec. 19, 1955 4 Sheets-Sheet 4 INVENTORS l/EA/RY 6-. Ark/ 5 BY Mum/w bf lyK/(EA/ A rrokvsys ft 1 Ce Patented .luly19, 1960 INTEGRATED DRY MATERIAL REDUCING AND CLASSIFYING IVIEANS Henry G. Lykken, Minneapolis, and William H. Lykken, Edina, Minn., assignors to The Microcyclomat Co., Minneapolis, Minn., a corporation of Delaware Filed Dec. 19, 1955, Ser. No. 553,792

15 Claims. (Cl. 241-41) This invention relates to integrated means for reducing and classifying dry solid particulate material. Combination reducing means and classifying means for regulating the particle size of the product and returning oversize material to the grinding zone are well known in the milling art. This invention, however, is dedicated to a large and increasing number of materials that must be reduced to a given mesh or micron dimension, but with as little as possible of finer material.

There must be as little as possible of superfine particles, that is, the least possible overgrinding, even if the wanted maximum particle size is in the subsieve range as low as all minus one micron. For a given use, the specifications may call for particles to be all through any given sieve size or all minus any given micron dimension, very frequently in the range from all minus 50 microns to all minus microns, or even all minus one micron, with as little as possible reduction beyond the specified optimum size.

The achievement of these results necessitates, in the grinding process, the immediate and complete removal of the desired particle size and finer from the grinding zone as fast as they are produced. It necessitates merging the processes of reduction of material and classification, making of them a complex, integrated and interdependent process. 7

It is the principal object of this invention to provide an integrated dry material reducing and classifying means and an integrated dry material reducing and classifying method.

With slight modification, as pointed out in detail hereinafter, the integrated reducing and classifying means maybe operated primarily as an independent classifying unit where quantity production and precise classification are called for. When so modified and operated there is provided one rotor which, instead of functioning as a milling or reducing rotor, acts as a segregating rotor to reduce agglomerates, thoroughly disperse, fluidize and aerate the material and to segregate out and extract the fines and near fines. The fines and near fines are discharged to a superposed classifier rotor which withdraws the desired fines and returns the near fines. The coarser oversize is progressively removed from the bottom of the segregating rotor.

A further object of this invention, therefore, is to provide an independent two stage precision aerodynamic classifying means andmethod.

Other objects of the invention will become apparent as the description proceeds. I i

To the accomplishment of the foregoing and related 'ends, this invention then comprises the features herein- :after fully described and particularly pointedout in the claims, the following description setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a fewof thevarious ways in which the principles of the invention maybe employed.

The invention is illustrated by the drawings which the same numerals refer to corresponding parts and in which:

'Figure 1 is an end elevation, in section, of the integrated grinding and classifying means of this invention, the section taken along the line 1-1 of Figure 2 and in the direction of the arrows;

Figure 2 is a side elevation, in section, taken along the line 2-2 of Figure 1 and in the direction of the arrows;

Figure 3 is a fragmentary section showing an alternative form of rotor construction;

Figure 4 is an end elevation, in section, of a modified form of construction adapted to function primarily as an aerodynamic classifier, the section taken along the line 4-4 of Figure 5 and in the direction of the arrows; and

Figure 5 is a side elevation, in section, taken along the line 5-5 of Figure 4 and in the direction of the arrows.

In the apparatus and method of this invention, the desired particle size and finer are discharged from the grind mg load everyrevolution of the mill rotor, in fact, every three-fourths revolution of the rotor. By means such as variation in rate of rotor speed, type and number of rotor blades, running clearance, rates of feed and air flow, type of mill liner and the like, the grinding itself may be controlled to minimize excess fines or the apparatus can be made to function as an independent clas= slfier with little or no reduction of particles.

Referring to Figures 1 and 2 of the drawings, the integrated system comprises a mill and a classifier. 'I'he classifier is shownmounted on a mill of the type described in copending' United States "application Serial No. 497,194, indicated generally at 10. The'mill'comprises agcnera1ly horizontal housing 11, preferably provided with a liner 12, which may be smooth or corrugated. Housing 11 is enclosedbetween two end plates 13 and 14. It will be noted that this mill is' characterized by the absence of a self-contained fan. The end plates extend to a base or floor and are 'afiixed by the floor flanges.

A suitable bearing structure adequately sized to carry the rotor of the mill is mounted at each end of the mill outside the end plates. Upon the bearings there is mounted a shaft 15 extending through theend plates and running the entire length of the mill forming the axis thereof. 'Shaft 15' is driven by any suitable drive means. Shaft 15 is enlarged'and reinforced through part of'its length by a tube 16 supported by annular rings 17 welded'or otherwise securedto sleeves keyed to the shaft, the shaft, tube and annular rings forming a rigid unitary structure upon which the grinding rotor units are mounted. V

A rotor end disk 18 is mounted on each end of the tube secured to one of the annular rings. Mounted in series between the rotor end disks are a plurality of individual independent radial blade grinding or pulveriz ing units 19. As shown, each unit comprises an annular disk 26 perpendicular to the shaft carrying in radial slots around its periphery a plurality of flat radial blades 21 enclosed between a pair of disks 22. 'Radial blades 21 are positioned perpendicular to the slotted disk. Disks 22 have a diameter reaching to the periphery of blades 211' The slotted disks 20 and disks 22 are'held spaced apart by annular spacer'rings 23 of appropriate length keyed-to tube 16. Radial blades 21'm'ay likewise be in the form of rods mounted perpendicular-to the rotor disks. Each rotor pulverizing unit acts as complete independent annular grinding zone from-feed to finished product. r 1 l The upper forward quadrant of the cylindrical mill housing 11 is cut away and replaced by an upwardly extending section defined between the end plates .13 and 14 by a generally tangentialfront wall 24 and the rotor and forming an expansion chamber and mill outlet 25.

Below this expansion chamber along the center line'of the housing is a lip forming a tangential opening 26 extending the length of the housing for both air and the material to be reduced.

A material and gas inlet means indicated generally at 27 is provided along the full length of the mill forcontrollably feeding the material to be reduced to the inlet opening 26. In the form here illustrated the -material feeder comprises an elongated hopper 28 with a rotary metering gate 29, preferably driven by a variable speed drive for precise feed rate control. The hopper may be fed from any suitable source.

An air inlet chamber 30 is provided .below the feed hopper. The air inlet A has a sliding gate or damper 31 associated with the tangential inlet 26 for precise inlet air control. By these means the material 'as fed isdrawn into the mill with the air and forms a fluid suspension of solid material in air.

The bottom of the mill housing is provided with an opening 32 or a plurality of openingsalong the length of the mill, connected with an outlet gate or duct having slide dampers 33 or similar means for progressively withdrawing bits of sand, stone, grit, metal and like extraneous heavier material from the mill -load. Initially this grit trap will become filled with the material to be reduced, but as grit and like material is introduced into the mill along with the feed, it will, because of its greater density, drop ,to the bottom of the trap.

As shown here, the outer edge of the damper 33 is supported by a rod or roller 34 or similar support. The upper surface of theslide damper is provided with one or more racks 35 whose teeth mesh.with the teeth of pinions 36. The -.shaft bearing pinion 36 is suitably provided witha lever or crank handle for adjusting the slide, or preferably is provided with a variable speed drive synchronized with the feeder drive to discharge a predetermined fixed percentage of the feed through the grit trap.

The classifier housing, indicated generally at 37, comprises a generally cylindrical rotor housing 38 enclosed between two end plates 39 and 40 and mounted on top of the mill housing. A fan housing 41 is mounted at one end of the classifier and comprises a fan housing Wall 42' enclosed between classifier end plate 39 and fan end plate 43.

A suitable bearing structure adequately sized to carry the common rotor of the classifier and fan is mounted outside of end plates 40 and 43. Upon the bearings there is mounted a shaft 44 extending through the end plates and running the entire length of the classifier and fan housing forming the axis thereof. Shaft 44 is driven independently of shaft 15 and in the opposite direction by any suitable drive means. Shaft 44 is enlarged and reinforced through part of its length by a tube 45 supported by annular rings 46 and 47 welded or otherwise secured to sleeves keyed to the shaft, the shaft, tube and annular rings forming a rigid unitary structure upon which the classifying rotor units are mounted. End plate 39 has a large annular opening to permit passage of the rotor to the fan housing.

A rotor end disk 48 is mounted on annular ring 47 at one end of the rotor tube and a fan disk or plate 49 is mounted on annular ring 46 at the opposite end of the tube. Distributor fan blades 50 are mounted on fan plate 49. Splines 51 mounted on tube 45 and fan plate 49 support a second classifier end disk or annular ring 52 within the classifier housing. Ring 52 carries small impeller blades 53 in the space between the end of the classifier portion of the rotor and the classifier housing end plate to create a slight positive pressure around the periphery of rotor end disk 52 to prevent particles from being withdrawn around the end of the rotor.

Mounted in series between the classifier rotor enddisks 48 and 52 are a plurality of spaced annular classifier disks 54 and 55 supported by tie bolts 56 and held apart by through the opening.

spacer washers 57. Disks 55 are of greater outside diameter than disks 54 but less than the outside diameters of end disks 48 and 52. All of disks 54 and 55 have a greater inside diameter than the outer diameter of tube 45 to form an annular axial passageway 58 to the fan housing for withdrawal of particles from the classifier rotor. The enlarged diameter of the rotor end disks, extending beyond the mean diameter of the rotor, insures a uniform circulation of the material in the classifier rotor chamber free from axial shifts. The spaces between the rotor disks form radial passageways communicating with the axial passageway. A conical spacing member 59 makes the annular axial passageway of gradually increasing cross-section in the direction of the fan and product discharge and thereby assists in unifying flow through the classifier.

The lower forward quadrant of the cylindrical classifier housing 37 is cut away and replaced by a downwardly extending section defined between the classifier end plates 39 and 40 by a generally tangential front wall 60 and the classifier rotor and forming a classifier inlet 61. Inlet 61 is directly above and in communication with expansion chamber and mill outlet 25.

A second controlled air inlet B is provided immediately above the mill rotor discharge the full length of the mill in the space between the top of mill housing wall 11 and plate 62 which is between the mill and classifier housings. A slide damper 63 is-positioned in the inlet opening to regulate the passage of air.

A third controlled air inletport C is provided just below the circulating classifyingair fiowthe full length of the classifier, in the space between the bottom of classifier housing wall 38 and plate 62. A slide damper 64 is positioned in'the inlet opening toregnlate the passage of air In Figure 1 both air inlets B and C are shown closed.

A product discharge duct 65 is provided from fan housing 41. 'This duct in turn will be connected to any conventional air separator or collector (not shown) for recovery of the product. Where desired or necessary, as in the case of a long mill and classifier, an exhaust chamber and discharge outlet may be provided for both ends of the classifier. The fan'mounted on the shaft within the exhaust chamber is of the distributing type. Since the classifier rotor is to be operated at selected speeds independent of the air flows, the exhaust chamber is connected to an independent exhaust fan associated with the collector.

An alternative form of classifier rotor structure is shown in Figure 3 wherein solid rotor-disks 54 and 55 are replaced with pairs of thin spaced apart annular disks 54A and 55A. Thesepairs of disks are held spaced apart from one another by spacer washers or annular spacer rings 66 and-are held spaced apart from other pairs of disks by spacer washers 57.

In the operation of the integrated system the feedmaterial is metered into the mill housing from hopper 28 throughtangential inlet 26 along the entire length of the mill. At the same time air is introduced to form a iluidal suspension of the material. The mill rotor acts as a pcripheral air inlet fan with corresponding air inlet ports, ducts, passages and control means.

By" means of damper 31 air flow A into the mill rotor chamber is precisely controlled as to volume, circulation in the grinding chamber, outlet velocity and lift or air drag out of the chamber, all independently of the larger and varying air flows required in the classifying process.

"In amanner well known in this art the dry solid material becomes reduced in the course of its passage around the rotor housing with the rotor by high velocity impact and fiuidal vortex action. For a detailed description of the mechanism by which attrition and reduction of the particles takes place reference is made to Henry G. Lykken, UnitedStates Patent No. 2,294,920, issued September 8, l94 2 or N o. 2,717,741, issued September 13, 1955.

intrablade -It does not involve circulation of a mass of material on a corru gated line. The mill operates with a highly fluidal mill load which is continuously sucked into the rotor at and by the back of each blade and discharged by the forward face of the next or trailing blade. The larger and granular particles are reduced by metallic blade impact each time they enter or attempt to enter the rotor with further reduction by the intense intrablade vortex action within the periphery of the rotor.

The mill of this invention is a fluid energy mill. While the larger and granular particles are reduced by continuing high velocity metallic beater impact the fractured and finer material is reduced by its high intensity intrablade fluidal vortex action induced and maintained by a very high velocity air flow alternating in and out through the periphery of the rotor back of each blade.

Fluid energy as applied to the so-called jet mills is a single high velocity impulse almost instantly dissipated.

ity induced and maintained by the rotor with the oversize continuously returning until completely reduced.

In the course of three-fourths of a revolution of the rotor the material is reduced and the particles of desired particle size and finer are thrown out into the expansion chamber 25 and withdrawn. The larger and heavier particles are thrown tangentially outwardly and downwardly into the expansion chamber space and fall back into the rotor for another revolution and further reduction.

Controlled air inlet B provides a supplementary air flow immediately above the rotor discharge to supplement the lift air and insure that all of the fines, which will include a margin of near fines, will enter the classifier zone and remain in constant circulation until all of the fines are extracted. The near fines and any oversize particles carried to the classifier zone with the In the finer particle size ranges an increasing amount of air is required for classification to provide greater dilution of the product as the fineness increases. Where needed, this additional air is provided by controlled air flow C which is sucked into the classifier by an exhaust fan connected to the classifier discharge.

The particles of desired size and finer are drawn radially inwardly from the peripheral inlet of the classifier rotor, through the spaces between the annular classifier disks to the annular axial passageway and thence to the fan housing and the discharge outlet. Since the classifier rotor operates at selected speeds independent of the air flows, the particles are drawn through the classifier largely by suction created by an independent exhaust fan associated with the collector. Particle size selection and precision of classification depend not only upon precision of air fiow control through the classifier but also upon constant outlet suction that can be regulated and set by the mill operator and preferably maintained automatically.

The classifier rotor is operated at a speed that will impart the desired centrifugal throwout effect to the particulate material in suspension in the air peripherally In this system the near fines Thethrowout effect counteracts the inward drag of the air in its properly distributed and controlled flow, limiting thedimension of material that will go in with the air. The particle size can be changed by varying either of all kinds, with or without grinding effect.

the'classifier rotor speed or the air fiow. Preferably particle size is controlled by regulation of air flow. Total air flow will range from about 20 to 80 cubic feet per minute per pound of product. Instant discharge and removal of the finished product every revolution of the reducing rotor is a factor which increases mill efficiency by 100% or more. t

The apparatus of this invention is adapted for the processing of sugar and mixes containing a substantial percentage of fat. It is particularly adapted for fine grinding cocoa and cocoa mixes, even high fat cocoa, and other heat sensitive materials in hot weather. A percentage of Dry Ice may be admixed with the feed to chill the incoming material and continuously chill the oversize as it returns to the feed every revolution of the-"rotor. Thus chilled, the material fractures rather than splatters.

. The unit can be operated as an effective and efficient blender, homogenizer and conditioner for dry mixes With slight modificationthe integrated reducing and classifying means can be operated as an independent classifier.

Where milling requires the reduction of a homogeneous product to a given size and finer, adequate classification may be. provided by a classifier integral-with the and finer with no oversize, many other specified size and finer with no oversize in the range from one micron up to 50 microns, .is a problem involving. precise air proportioning, distribution and controls. Lnthis range the material to be classified becomes, in effect, a fluid and must be treated as a fluid. a The finer the endproduct is, themore that fact becomes apparent. As the wanted end-product increases in fineness, greater dilution in air is required ona proportional basis.

The classifying process-calls for: a

(a) Continuous, complete, uniform dispersal and. suspension of all of the material in air at every stage of the process.

(b) A controllable progressive segregation of the wanted particle size and finer from the oversize.

(c) A series of well considered controllable aerodynamic reactions designed to continuously retard and eliminate the oversize and continuously extract the wanted particle size and finer with the air flow.

(d) Controllable means for segregating the oversize and continuously removing it from the classifier. 55

(e) Controllable means for regulating each air flow and its aerodynamic reaction to regulate and obtain the desired end product with no oversize and as nearly as possible 100% extraction. 1

With minor modification the integrated reducing and classifying means of this invention can be adapted as an aerodynamic classifier designed on this basis. As shown in Figures 4 and 5 the aerodynamic classifier includes a lower segregating rotor built up of a series of closed end units 19A, mounted axially in a horizontal cylindrical housing 10A having degrees of its circumferenceexpanded into a fine discharge and outlet chamber, 25. This outlet chamber is connected to the super-imposed classifier chamber 37 containing a centripetal classifier. rotor.

The objective of the lower rotor, is to reduce aggloirr. crates, fluidize and aerate the material to be sorted and to segregate out and extractthe'fines and near fines and to discharge them at the top of the rotor. -All ofthe coarser oversize remainsin. the diametrically lopposite 7 5' enlarged lower chamber 67 from which it is progressively removed. Only the fines-wanted particle size and finer and near fines enter the superimposed classifier chamber 37. i

The lower segregating rotor includes a plurality of fluidal, not a heavy mass of circulating material. High mill capacities require considerably less than one quarter inch depth of material.

The dry material to be classified is fed from the hopper 28 by metering gate 29 to the rotor along the full length of the rotor and is discharged continuously at the top of the rotor. A regulated amount of air (airflow A) enters with the material. The rotor itself acts as a peripheral suction and peripheral discharge fan. It induces the air and material into the segregating chamber and discharges it at the top of the chamber under velocity pressure. Some of the air will recirculate, as well as any oversize that escapes the outlet trap chamber 67 at the bottom of the rotor, along with near fines returned from the classifier chamber and some minor percentage. of fines.

It will be noted that the air flow A, hence air lift out of the segregating chamber, can be so regulated at its inlet that only fines and near fines escape to the classifier chamber. For convenience of this regulation, a secondary air inlet in which control damper 63A is positioned is provided immediately above the rotor discharge for secondary lift air supply B. It enters at right angles to the upward fiow to give a uniform desired flow pattern in the uptake section as well as adequate controlled lift air.

All fines must be lifted out and remain out. All near fines, as they accumulate in the classifier circulation, must break through and return to the lower chamber. This they will do on the basis of a negligible size differential. The problem is to minimize the return of the wanted particle size material.

Housing 11A of the segregation rotor and its optional inner liner 12A, extend generally tangentially downwardly opposite the open expansion chamber and discharge outlet to provide an oversize particle outlet trap 67 below the segregation rotor. This space progressively fills with the circulating oversize. The unique suction action of the rotor maintains it in an activated condition, constantly removing the fines and allowing only the oversize to accumulate. The oversize is progressively removed from the bottom of the trap by a reciprocating slide outlet 68 interlocked with the feeder drive so that a precise percentage of material fed can be withdrawn.

The slide outlet 68 is provided with one or more racks 69 whose teeth mesh with the teeth of pinions 70. The shaft bearing pinion 70 is provided with means for reciprocating the slide, preferably a variable speed drive synchronized with the feeder drive to discharge a predetermined fixed percentage of the feed through the oversize outlet.

The oversize outlet discharges through an opening 71 into a chute 72 from which the oversize iscollected. The size of the outlet slide opening 71 and chute 72 are determined largely by the nature of the product being classified and the reason for classification. In some instances the oversize particles may be the desired product in which case oversize would make up the predominant portion of the feed. In this event, the purpose of classification is to remove fine or superfinefrom the desired particle size. Further refinement can. readily be provided to regulate the rate of withdrawal of the oversize,

8 independently and automatically, based upon variation in the mill load itself.

A pressurized air flow D is provided at the base of the outlet pocket 67 for resifting the tailings, where necessary or desirable. This air flow is regulated and controlled by a slide damper 73 between the bottom wall of the rotor housing and the slide outlet 68.

The superimposed classifier chamber 37 is cylindrical with 90 degrees of its circumference cut out and conneoted to the discharge 25 from the lower chamber 10A. A radial inlet and axial outlet rotor is mounted axially in this chamber discharging axially into an outlet chamber 41 which is connected to an outlet duct 65 to carry away the air and fine product to a collector system. The fan unit 49-50 on the shaft of the classifier rotor is not an adequate outlet fan since the classifier rotor is operated at relatively low speeds of the order of 500 to 1000 r.p.m. This fan is merely a means to insure uniform distribution of the axial suction.

The aerodynamic classifier requires a uniform constant airflow through the system, hence anniform constant suctionin the outlet chamber and duct. The suction must be under the control of the operator as he adjusts the various air inlets and must remain as set. This presupposes a connection to a collector fan having adequate volume and static capacity with controls at the classifier inlet. The classifier rotor as illustratedis the spaced annular disk type shown in detail in Figure 3.

' Several variations of centrifugal classifier rotors per se,

, each comprising spaced annular disks, a peripheral inlet and axial outlet and adapted for use in the system of this invention are described in detail in copending United States applications. Serial No. 278,239, filed March 24, 1952, now Patent No. 2,754,967; Serial No. 306,126, filed August 25, 1952, now Patent No. 2,741,366; Serial No. 410,854, filed February 17, 1954; Serial No. 505,118, filed May 2, 1955, and others.

Rotation of the rotor subjects the particles entering the rotor, thoroughly distributed and dispersed in air, to centrifugal stresses in proportion to their mass or individual dimensions. Even at nominal rotor speeds such stresses will be several hundred times gravity. This requires a substantial compensating force (air drag) hence centripetal air velocity to induce a given particle size into the classifying rotor.

In practice, depending upon the specific gravity of the material, shape of the particle and wanted particle size, a best rotor speed can be established. The particle size withdrawn will then vary with the centripetal air velocity or the air flow through the rotor. At a given rotor speed, increasing the air flow increases the particle size and decreasing the air fiow reduces the particle size. A fixed air fiow may be used by varying the rotor speed. It is preferred, however, to use a constant rotor speed to avoid higher than necessary speeds and to conserve air flow.

Classification of finely divided material calls for a relatively high air dilution and dispersal in the air. It constitutes, in fact, the largest percentage of the air requirement. In the aerodynamic classifier the additional air for classification is controllably supplied at the inlet of the classifier chamber. It enters inlet C as a horizontal flow below the circulating material in the chamber 37 and constitutes, with the other air inlet ports and air flows, means for controlling and regulating the aerodynamic actions and reactions called for in the process.

Both the segregating rotor and classifying rotor are operated 'at relatively low speeds ranging from about 500 r.p.m. to 1000 r.p.m. as a maximum. 'Ihey revolve in opposite directions. The rotors are preferably driven by individual motors, one supported above the other.

Replaceable liners 12A are provided in the segregating rotor chamber and can also be provided in the classifier chamber. Liners may be stainless steel, wear resistant steel or other material. Thesegregating rotor blades 21A may be steel rods or pipeor an assembly of steel core 9 V rods and segments of wear resistant, material, suchas rubber. The rods are round and readily replaceable. The spaced annular disks 54A, 55 and 55A of the classifier rotors may be made of aluminum, stainless or other steel or like material. The widths of the annular channels are varied readily by varying the thicknesses of the spacer washers 57 for the open channels and annular spacer rings for closed channels. The'rotors can be assembled with any desired width' of open-channel as well as any desired percentage of open channel.

The rotors are readily assembled and reassembled in the field. The rotor chambers are preferably split horizontally so that the superstructures may be lifted oil. The rotor blades and liners may be replaced with the segregating rotor undisturbed or the rotor may be lifted out.

The aerodynamic classifier, when fittedwith a standard open reducing rotor, instead of the segregating rotor, and operated at higher speeds, becomes an integrated selfclassifying mill. The oversize outlet is then used only for accumulation and removal of sand, grit, tramp metal, etc. Conversely, when the reducing rotor of the integrated reducing and classifying means is replaced with a segregatthe bottom of -,the classifier chamber 'overabout on quadrant thereof connected directly to the peripheral dising rotor the unit operates as an aerodynamic classifier. It is apparent that many modifications and variations of this invention as hereinbefore set forth may be made without departing from the spirit and scope thereof. The specific embodiments described are given by Way of example only and the invention is limited only by the terms of the appended claims. I

What is claimed:

1. Integrated means for processing dry material which comprises a horizontal open rotor unit having a generally cylindrical rotor chamber, said rotor comprising a plurality of closed end radial blade units having peripheral suction intake and peripheral discharge, said rotor constituting a peripheral suction intake fan, a tangential air and material inlet port at one side of said rotor chamber the full length of the rotor, means for regulating the intake of material and air through said inlet, a peripheral discharge opening at the top of said rotor chamber over about one quadrant thereof, an air inlet port at the top of said rotor chamber for admitting a flow of air tangential to the periphery of the rotor, means for controlling the air intake through said inlet port, a classifier unit superimposed upon said rotor unit and having a horiontal and generally cylindrical classifier chamber, a peripheral intake and axial outlet centripetal classifier rotor journalled axially in said chamber, a peripheral inlet at the bottom of said classifier chamber connected directly to the peripheral discharge opening of the reducing chamber, an air inlet port at the bottom of the classifier chamber tangential to the peripheral flow of the classifier rotor, means for controlling the air intake through said inlet port, an outlet suction chamber associated with the axial discharge of the classifier rotor and means to maintain a regulated suction in said chamber.

2. In an integrated means for processing dry material,

' a generally cylindrical horizontal rotor chamber, a closed end vortex action radial blade rotor mounted axially in said chamber, a tangential air and material inlet port at one side of said rotor chamber the full length of the rotor, means for regulating the intake of material and air through said inlet, a peripheral discharge opening at the top of said rotor chamber over about one quadrant thereof, said discharge opening being disposed at the same side of the rotor chamber as the air and material inlet port, an air inlet port along the length of the rotor at the top of said chamber for admitting a flow of air tangential to the periphery of the rotor and means for controlling the air intake through said inlet port.

3. An integrated means according to claim 2 further characterized by a generally cylindrical horizontal classifier chamber mounted above said rotor chamber, a peripheral intake and axial outlet centripetal classifier rotor journalled axially in said chamber, a peripheral inlet at charge opening of the reducing chamber, an outlet suction chamber associated with the axial discharge of the classifier rotor and means to maintain a regulated suction in said chamber.

4. An integrated means according to claim 3 further characterized by a supplementary air inlet port at the bottom of the classifier chamber along the length of and tangential to the peripheral flow of the classifier rotor and means for controlling the air intake through said inlet port,

5. An integrated means according to claim 3 further characterized in that said classifier rotorcomprises an assembly of spaced annular disks of uniform diameter divided into sections axially by spaced annular disks of substantially larger diameter.

6. An integrated means according to claim 2 further characterized in that said rotor comprises a particle segregating rotor including a plurality of spaced discs supporting a plurality of parallel spaced longitudinally extending rods about their periphery.

7. An integrated means. according to claim 6 further characterized in that the rotor chamber is provided with an enlarged oversize particle outlet in its lower quadrant disposed diametrically opposite the peripheral discharge opening at the top of the rotor chamber.

8. An integrated means according to claim 7 further characterized in that a horizontal longitudinal air inlet into the oversize particle outlet is provided at the bottom of the rotor chamber tangential thereto along its length.

9. Integrated means for reducing and classifying dry material to an optimum particle size free from oversize and with a minimum of overgrinding and finer particles which comprises a horizontal open rotor mill unit having a generally cylindrical reducing chamber, the rotor of said mill comprising a plurality of closed end radial blade reducing units having peripheral suction intake and peripheral discharge, said rotor constituting a peripheral suction intake fan, a tangential air and material inlet port at one side of said reducing chamber the full length of the rotor, means for regulating the intake of material and air through said inlet, a peripheral discharge opening at the top of said reducing chamber over about one quadrant thereof, an air inlet port at the top of said reducing chamber for admitting a flow of air tangential to the periphery of the mill rotor, means for controlling the air intake through said inlet port, a classifier unit superimposed upon said mill unit and having a horizontal and generally cylindrical classifier chamber, a peripheral intake and axial outlet centripetal classifier rotor journalled axially in said chamber, a peripheral inlet at the bottom of said classifier chamber connected directly to the peripheral discharge opening of the reducing chamber, an air inlet port at the bottom of the classifier chamber tangential to the peripheral flow of the classifier rotor, means for controlling the air intake through said inlet port, an outlet suction chamber associated with the axial discharge of the classifier rotor and means to maintain a regulated suction in said chamber.

10. In an integrated reducing and classifying means for dry solid materials comprising a generally cylindrical horizontal reducing chamber having a reducing rotor mounted axially therein, a controlled tangential air and material inlet port at one side of said reducing chamber the full length of the rotor and a peripheral discharge opening at the top of said reducing chamber, the improvement which resides in an air inlet port along the length of the rotor at the top of said reducing chamber for admitting a flow of air tangential to the periphery of the reducing rotor.

11. In an integrated means for reducing and classifying dry material to an optimum particle size free from oversize and with a minimum of overgrinding and finer particles, a generally cylindrical horizontal reducing chamber, a closed end radial blade reducing rotor mounted axially in said chamber, a'tangential air and material inlet port at one side of said reducing chamber the full length of the rotor, means for regulating the intake of material and air through said inlet, a peripheral discharge opening at the top of'said reducing chamber over about one quadrant thereof, an air inlet port along the length of the rotor at the top of said reducing chamber for admitting a flow of air tangential to the periphery of the reducing rotor and means for controlling the air intake through said inletport.

12. An integrated reducing and classifying means according to claim 11 further characterized in that said reducing rotor is mounted in said reducing chamber as a peripheral suctionfan and having a peripheral discharge tion.

13. An integrated reducing and classifying means according to claim 11 further characterized by a generally cylindrical horizontal classifier chamber mounted above said reducing chamber, a peripheral intake and axial outlet centripetal classifier rotor journ'alled axially in said chamber, a peripheral inlet at the bottom of the classifier chamber over about one quadrant thereof connected directly to the peripheral discharge opening of the reducing 15 within the chamber to produce a positive pressure condit chamber, an outlet suction chamber associated with the axial discharged the classifier rotor and means to maintain a regulated suction in said chamber.

14. An integrated reducing and classifying means accordingto claim 13 further characterized by a supple mentaryi air inlet port at the bottom of the classifier chamber along the length of and tangential to the peripheral flow of the classifier rotor and means for controlling thetair intake through said inlet port.

15. An integrated reducing and classifying means according to claim 13 further characterized in that said classifier rotor comprises an assembly of spaced annular disks of uniform diameter divided into sections axially by spaced annular disks of substantially larger diameter.

References Cited in the file of this patent UNITED STATES PATENTS 1,305,413 Schutz June 3, 1919 2,219,720 Clark Oct. 29, 1940 2,487,941 Peterson Nov. 15, 1949 2,717,741 Lykken Sept. 13, 1955 2,728,456 Lykken et a1. Dec. 27, 1955 FOREIGN PATENTS 750,314 Germany May 12, 1943 

